The LSU AgCenter Rice Research Station has a long history of developing new varieties of benefit to the Louisiana rice industry. In fact the station was first established for that purpose in 1909. Additional research projects were added over the past 96 years, but variety development has always been a major focus of the station’s research activities.

Variety development takes a great deal of: 1) time, 2) money, 3) hard work and travel on the part of a large number of people, 4) specialized field and laboratory equipment and 5)cooperation. The Rice Station is fortunate to have a dedicated group of people who will devote the time and work ethic necessary for variety development to be successful. We also are fortunate to have financial support for these activities. Especially important to us is the funding received from rice producers through the Louisiana Rice Research Board.

To develop a new variety, we must first develop new genotypes (or genetic combinations). We do this by making crosses between two different rice lines. Since the rice flower is perfect (contains both the male and female flower parts) we must artificially create a female flower. We do this by removing the male flower parts (anthers) from a rice floret. This is normally done by using a small pipette connected to a vacuum pump which basically vacuums the anther out of the flower. This is a tedious process that must be done in a meticulous manner. We can then introduce pollen from a different line and pollinate that (female) flower.

Over 1,000 such crosses are typically made at the Rice Research Station each year. The resulting seed from these crosses will contain genetic information from both parents. This seed is called the F1 and we will germinate these to produce F1 plants. At maturity we harvest the seed from the F1 plants. This seed is bulk-planted the following growing season to produce a population of segregating F2 plants. Basically, segregation means that there is a great deal of variation in the appearance of these plants as they are expressing traits from both parents in many different combinations. Selection in the F2 populations is an important step in the variety development process. Breeders want to select those plants with the best combination of traits. We are often asked what we look for when making selections, and the best answer is EVERYTHING. Examples here include (but are not limited to) seedling vigor, maturity, height, tillering (number and uniformity), panicle size, completeness of panicle exertion, grain shape and appearance, disease resistance and overall plant appearance. We will select individual panicles from those plants expressing the best combinations of the traits listed above for advancement to the next generation and beyond.

From this point on (F3-F?), most of the breeding material is grown as panicle (head) rows. A panicle row is a row of plants all coming from seed off a single panicle the previous generation. Also, from this point on we will typically select the best rows (not individual plants) to advance to the next generation. Important to remember here is that with each generation, the amount of segregation is decreased (or the level of uniformity is increased). Each year we will grow out between 85,000 -95,000 panicle rows at the station in the various breeding projects. My personal goal is to keep the number under 100,000. Each of these rows is a different genotype, and any of them could theoretically become a new variety.

There is a tremendous amount of meticulous work that must be done before these rows are planted. The seed for each row must be individually threshed. Although we have a specialized panicle thresher to accomplish this, not too many years ago this was all done by hand. We also have specialized planters to plant the individual rows. Even with some mechanization, the process still requires a great many hours of meticulous work to load this seed for planting in such a way as to avoid mistakes.

For most of our crosses we have reached sufficient uniformity by the F4 to F5 generation to enter a line into initial yield evaluation. Those lines selected for potential yield evaluation are bulk-harvested (after a selected number of panicles have been removed). Our bulk-harvesting of individual rows is done the old-fashioned way. We harvest each selected row by cutting the stalks with a sickle and then tying the harvested stalks with a length of twine. Each individual row is then threshed, aspirated and dried on a small-sample drier. Several thousand rows are handled this way each summer. During the following winter, we will conduct a number of analyses on each harvested sample (grain appearance and milling, cereal chemistry, seedling vigor) and the superior lines are entered into our preliminary yield test.

Next month we will discuss yield evaluation, purification, seed increase and the decision making process for a rice variety release.